2. Field of the Invention
This invention relates to domestic or industrial fuel spray combustion devices, and more particularly to a small fuel spray combustion engine for vehicles.
2. Description of the Prior Art
In a conventional fuel spray combustion device, as disclosed by Japanese Laid-Open Patent publication No. 147921/1984, a swirl chamber is provided at the center of a swirling air stream forming unit, a fuel jet nozzle for spraying fuel from the closed end of the swirl chamber towards the open end is connected to the swirl chamber in such a manner that it is coaxial with the swirl chamber, a first combustion cylinder is connected to the open end of the swirl chamber, a second combustion cylinder is connected through a first choke to the outlet of the first combustion cylinder in such a manner that it is coaxial with the first combustion cylinder, the second combustion cylinder being larger in diameter than the first combustion cylinder, and a second choke is provided at the outlet of the second combustion cylinder.
As is apparent from the above description, in the conventional combustion device, the second combustion cylinder is larger in diameter than the first combustion cylinder; that is, the combustion cylinder assembly is of an expanded tube type that a tube is expanded at the end. Therefore, the body of the combustion device, comprising the first and second combustion cylinders, is relatively large in diameter. Therefore, a car heater formed by putting a heat exchanger on the body is relatively bulky. In other words, it is difficult to provide a small car heater by using the conventional combustion device.
As the combustion cylinder assembly is of the above-described expanded tube type, the combustion flame is also expanded towards the end, and especially it becomes unstable in the small fuel flow region. Therefore, sometimes fuel is not satisfactorily burnt, i.e., the range of combustion is small.